<!DOCTYPE HTML> 
<html> 
<body> 
<canvas id="myCanvas" width="500" height="500" >your browser does not support the canvas tag </canvas> 
<script type="text/javascript"> 
var canvas = document.getElementById('myCanvas'); 
var ctx = canvas.getContext("2d"); 
var angle = 0; 
var count = 360; 
var clrA = '#000'; 
var clrB = 'red'; 

function taiji(x, y, radius, angle, wise) { 
angleangle = angle || 0; 
wisewise = wise ? 1 : -1; 
ctx.save(); 
ctx.translate(x, y); 
ctx.rotate(angle); 
ctx.fillStyle = clrA; 
ctx.beginPath(); 
ctx.arc(0, 0, radius, 0, Math.PI, true); 
ctx.fill(); 
ctx.beginPath(); 
ctx.fillStyle = clrB; 
ctx.arc(0, 0, radius, 0, Math.PI, false); 
ctx.fill(); 
ctx.fillStyle = clrB; 
ctx.beginPath(); 
ctx.arc(wise * -0.5 * radius, 0, radius / 2, 0, Math.PI * 2, true); 
ctx.fill(); 
ctx.beginPath(); 
ctx.fillStyle = clrA; 
ctx.arc(wise * +0.5 * radius, 0, radius / 2, 0, Math.PI * 2, false); 
ctx.arc(wise * -0.5 * radius, 0, radius / 10, 0, Math.PI * 2, true); 
ctx.fill(); 
ctx.beginPath(); 
ctx.fillStyle = clrB; 
ctx.arc(wise * +0.5 * radius, 0, radius / 10, 0, Math.PI * 2, true); 
ctx.fill(); 
ctx.restore(); 
} 

loop = setInterval(function () { 
beginTag = true; 
ctx.clearRect(0, 0, canvas.width, canvas.height); 
taiji(200, 200, 50, Math.PI * (angle / count) * 2, true); 
//taiji(350, 350, 50, Math.PI * ((count - angle) / count) * 2, false); 
angle = (angle + 5) % count; 
}, 50); 
</script> </p> <p></body> 
</html> 
